Semimechanical rectifier



June 12, 1928. 1,673,026

J. C. SCHELLENG SEMIMECHANICAL REdTIFIER Filed July 28, 1922 Wye/Monk/O/Y C. Sake/L977;

W L KZZMM Pmmd Jm 12, 1928;

UNITED STATES PATENT ossics.

JOHN G. SCHELLEKG,

YORK.

Application filedi July 28,

This invention relates to means for recti fying polyphsse siternsting current and, has for its object a combinsriori of circuits ami apparatus fifor rectifying poiyphese slficrnaiing currcricby the use of a minimum number of rectifying elemerics slid by means oi which spsrkiog will fsc eliminated: In accordance with the general features 053 this iriycntion, rccsificction of poiyphasc siterriscing current is accomplished by means of an cpgmrstus comprising two or more unilateral conducting eicmcets cooperating with two or more synchronous commutatorsi The mi-is cerci conducting demerits pissed is. series with. the circuit to which rectificci can is cc be deiivcred, ans she commute are srrcnged to make confisctics progr- :siveiy from the uni-1a "erai coriclucticg eiemen s to the source oi phase volt 'cge. This is done in such a manner that cscii source or phase vcitsge' is connected through c'se oi the rmi-iciuercl conducting eicrcccss so t-re dircci current; circuit during the portion of each when its phase voltage is than any other of she phase voltages, and for a short imcrysi beforc and after such periccs Fricr tc this invention, polyphase current keen reccificd by spvgsrecss in which a uniersi conducting eicment is connected to eccm source of phase voltage. This re: quires as merry uni-icrersi conducting eicxhcmss as there are phases in'thc polyphasc sysremg cmi each element must be capable of carrying substantially of jobs current. By means of the present lnvention the number of unilateral comiiiccing elements requires are reduced to s minimum, and since the ccmmutccors ere orrcriged so that the connection besircen a source of phase voltage and s uni-lscerai conducting element is undisturbezi (Earring? such time as thevoltsge of that phase is greater sham she voitcges of ail other phases no spcrkisgccri occur.

Fi Q 1 shows the invention soap-ted. to recti. I quarter-phase current;

Fig. shows the current and volmge rc= lation the circuit of Fig: 1; and

Fig 3 shows the inventlon adspred tify six phase currenta to rec= OF EAST ORANGE, NEW JERSEY, ASBIGKGR T9 WESTERN ELEC- TRIC COEPANY, 'INCQRPORATED, OF NEW YGEK, N.

Y., A. CORPORATIUK' 9F SEEIEECHAJQICAL RECTIFIER 1922. Serial No. 578,122"

Transformer primary windings 1 and 2 (Fig. 1} are energized from s two-phase three-Wire suppiy; smfi secondary windings 3 4, 5, and 6 are connected in star to give quarter-phase fourwirc empiric Desigmated as s whcle by 7 is c commutator having an insulating portion 8 a cons mating 7 portion 9-. Cocgiercvbirig with commutator 7 are brushes l0 and 11 comicctei cc windings 4 and 6, respec biwely as shows A second; commutator 12 has an insuiecing portion 13 and an conducting portion 14; and. cooperatirig with ccmmuracor 1% are brushes 15 and 16 connected to windings 3 5 'respcciziveiy. A slip-ring 1'? is ciecisricsiiy consected c0 9; and; a second. slip-ring 1% isciec= cricsiiy conneccco to is Oc-mmutaccls and 12, and slip-rings l'Z and 18 are recesses as shown on a shaft 139, having sections 20 and 21, crfi are driven s J chronism with the transformer Eu EL Fis by a motor %2 Making contact with slip-rimg i7 is s cm 11 23 connected to eisctrccls 24 rcctifying element 25 which may be of any WeiL kncwn type, an making contact with slipring 18 is a brush 26 connected to electrode 27 of a second similar recti element 28 Electrodes 29 and. 30 of rcctiiying elements 25 cm? 2-8 respectively, are ccnnecreiro gecher'b conucior 31 and placed in. series with s irect current load 32 by means of conductor 33. Lcsd 32 may a direct current rrmtor storage batteries to be charged,

or any ziggregccion of devices'which utilize tangles 9. show the time uring which commutator segment 9 is connected to winciings 4 or 6 as the case may be Gurvc shows to the same scale as curves 3, 4' 5' ami 6,

ahead of segment 14 and each of these segcally greater than all others, and winding 6 10' the voltage which is applied to the D. C. I circuit, Curve 3637383940 41- 42-43-44 shows approximately the direct current supplied tothe load by windings 6 as the result of phase voltage 6 The rectification of the quarter-phase current takes place as follows:

From a to b phase voltage 6 is algebraisupplies direct current represented approximately by curve 363738 by way of .com-

'mutator segment 9. At Z) phasevoltage 3' becomes the greatest, which causes the D. C. load to be transferred to winding 3 by way of commutator segment 14. At a the D. C. load is similarly transferred to winding 4, by way of commutator segment 9; at d, to winding 5; and at a back to winding 6 by way of commutator segment 9, etc.

Segment!) is mounted on shaft 19, 90

ments constitutes nearly half of the circumferenceof its commutator. These segments. are short enough to prevent short-circuiting of the transformer when the connec- 7 tions of the rectifying elements are being with sli ring 66, is a brush 68 the other windings.

transferred from one winding to the other.

No sparking can occur between the commutator and the brushes at the time of making and breaking connections, because at that time there is no tendency for the winding connected or disconnected to supply current. This may be seen from Fig. 2.

'Commutator segment 9 is connected to winding 6 from f to but that winding only supplies current from a to b; similarly for In Fig. 3, 45, 46, and 47 are three-phase transformer primary windings, and 48, 49, 50, 51, 52 and 53 are secondary windings connected in star to givesix-phase E. M. F. Cooperating with commutator 54 mounted on shaft 62, are brushes 55, 56, and 57, spaced 120 apart, and connected to windngs 49, 51 and 53, respectively. Cooperating with. commutator 58, mounted on shaft 62, are brushes 59, 60, and 61, spaced 120 apart and connected to windings 48, 50, and 52, respectively. Each commutator is composed of an insulating section which occupies. a trifle more than two-thirds of the circumference, and a conducting section which occupies a trifle less than one-third o f the circumference. Gommutator 54 is mounted so that its conducting section 68 is behind the conducting section 64 of commutator 58.

Electrically connected to 63 is a slip-ring and electrically connected to 64 is a slip- .ring 66. Making contact with slip-ring 65 is a brush 6? connected to electrode 71 of rectifying element 72; and making contact connected to electro e 69 of a second rectifying element 70. Electrodes 73 and 74 are connected together by a conductor 75 and placed in series with the D. C. load 76 by conductor 77. Conductor 78 completes the D. C. circuit back to the neutral of the transformer secondary.

Shaft 62 having insulating sections 79 and 80, is driven by motor 81 at synchronous speed.

. From the explanation previously given for Figs. 1 and 2, the operation of the circuit shown in Fig. 3 will beapparent to those skilled in the art.

The examples given by way of illustration are only two falling under the general case whose current, having a number of phases equal to m times a, is rectified, m and n being integers. I There are employed m rectifying elements and m commutators, each commutator having one conducting sector extending over an angle equal to or less than 21r n are n brushes.

This invention may be used to accomplish rectification'of current either for power or telephonic purposes, and it is obvious that many changes may be made without departing from the scope of the appended. claims. For example, the time of rotation of the commutator shaft could be made an integral multiple of the,-time of synchronous speed rotation.

The invention claimed is v 1. In combination, means for utilizing dis Cooperating with each commutator 'rect current'energy, a single pair of uni-lat-' uni-lateral conducting elements, theinumber of said elements and said commutators being less than the number of phases to be rectlfied.

2. In combination,means for utilizing di-..

rect current energy, a single pair of uni lateral conducting elements connected to said ut1l1z1ng means, a synchronous commutator connected to each of said uni-lateral conducting elements, brushes cooperating with sgid synchronous commutators, and a source 0 between said brushes and said utilizing means, the number of'said elements and said commutators being less than the number of phases to be rectified. I

3. In combination, means for utilizing direct current energy, a single pair of uni-lateral conducting elements connected to said utilizing means, a commutator connected to each of said uni-lateral conducting elements, three brushes cooperating with each ofsaid commutators, and a source of six-phase elecpolyphase electromotive force connected consumption clrcuit comprising a single tromotive force connected so that each phase voltage is applied between a brush and said utilizing means.

4. In combination, a source of polyphase voltage having a number of phases equal to m times n, muni-lateral conducting elements, m commutators each having a conducting segment extending over an angle of e 21 substantially n brushes cooperating wlth each of said commutators, and circuit connectlons'connecting a source of phase voltage to each of said brushes, and each commutator to one of said uni-lateral conducting elements.

5. An electrical system comprising, a source of polyphase voltage, a direct current pair of uni-lateral conducting elements, commutators for connecting the source of each positively increasing phase voltage to said direct current circuit at a time before its voltage becomes the greatest of the phase voltages and for disconnecting each source of phase voltage after its voltage has become less than another-of said phase voltages, the

number of said elements and said commutators being less than the number of phases 7 to berectified.

6. A rectifying system for polyphase current comprising a plurality of uni-lateral conducting elements and a plurality of switching devices associated with said unilateral conducting elements, the number of uni-lateral conducting elements and the number of switching devices each being less than the number of phases to be rectified.

7. An electrical system comprising a In witness whereof, I hereunto subscribe my name this 26th day of July A. 1)., 1922.

JOHN C. SCHELLENG. 

